Various models of automobiles are equipped with a fuel tank which has a filler pipe which extends upwardly from the tank along a slight inclined path toward the rear of the automobile, and then bends upwardly at a somewhat greater incline, terminating at a capped end located behind the license plate holder which is pivotal at its upper edge and serves as a door to give access to the filler pipe. Within the filler pipe, spaced from the cap end, is a hinged baffle or gate provided to prevent siphoning of gas out of the tank, and also to prevent the escape of fuel and fumes. This baffle or gate is opened by the nozzle of the gas supply hose when it is inserted by the attendant into the end of the filler pipe. It will be seen that an automobile fuel tank and filler pipe of the type just described presents a problem when an individual owner or a gas station attendant wants to add the contents of a quart can of additive into the fuel tank.
The same or similar problem is presented in automobiles in which the filler pipe extends from the gas tank out the side of the car. In such cars, the portion of the filler pipe containing the baffle is horizontal, or nearly so, for the first several inches from the cap end.